Long-Time Oxygen and Superoxide Localization in Cryptochrome.

Cryptochromes are proteins that are highly conserved across species and in many instances bind the flavin adenine dinucleotide (FAD) cofactor within their photolyase-homology region (PHR) domain. The FAD cofactor has multiple redox states that help catalyze reactions, and absorbs photons at about 450 nm, a feature linked to the light-related functions of cryptochrome proteins. Reactive oxygen species (ROS) are produced from redox reactions involving molecular oxygen and are involved in a myriad of biological processes.

Optimization of parameters in coherent spin dynamics of radical pairs in quantum biology.

Identification of the external electromagnetic fields and internal hyperfine parameters which optimize the quantum singlet-triplet yield of simplified radical pairs modeled by Schrödinger system with spin Hamiltonians given by the sum of Zeeman interaction and hyperfine coupling interaction terms are analyzed. A method that combines sensitivity analysis with Tikhonov regularization is implemented. Numerical results demonstrate that the quantum singlet-triplet yield of the radical pair system can be significantly reduced if optimization is pursued simultaneously for both external magnetic fields and internal hyperfine parameters.

Long-Time Oxygen Localization in Electron Transfer Flavoprotein.

Reactive oxygen species (ROS) exert a wide range of biological effects from beneficial regulatory function to deleterious oxidative stress. The electron transfer flavoprotein (ETF) is ubiquitous to life and is associated with aerobic metabolism and ROS production due to its location in the mitochondria. Quantifying oxygen localization within the ETF complex is critical for understanding the potential for electron transfer and radical pair formation between flavin adenine dinucleotide (FAD) cofactor and superoxide during ROS formation.

The Role of Pulsed Electromagnetic Fields on the Radical Pair Mechanism.

In recent decades, the use of pulsed electromagnetic fields (PEMF) in therapeutics has been one of the main fields of activity in the bioelectromagnetics arena. Nevertheless, progress in this area has been hindered by the lack of consensus on a biophysical mechanism of interaction that can satisfactorily explain how low-level, non-thermal electromagnetic fields would be able to sufficiently affect chemistry as to elicit biological effects in living organisms. This specifically applies in cases where the induced electric fields are too small to generate a biological response of any consequence.

Pilot study on the therapeutic potential of radiofrequency magnetic fields: growth inhibition of implanted tumours in mice.

The present study investigated possible therapeutic effects of radiofrequency or hypomagnetic fields on the growth rate of two types of implanted tumours. To this end, mice with implanted fibrosarcoma and pancreatic tumours were exposed continuously to a 2 µT, 10 MHz radiofrequency magnetic field (MF) perpendicular to a 45 µT static MF or to a hypomagnetic (~0.4-1 µT) field.

Arabidopsis cryptochrome is responsive to Radiofrequency (RF) electromagnetic fields.

How living systems respond to weak electromagnetic fields represents one of the major unsolved challenges in sensory biology. Recent evidence has implicated cryptochrome, an evolutionarily conserved flavoprotein receptor, in magnetic field responses of organisms ranging from plants to migratory birds. However, whether cryptochromes fulfill the criteria to function as biological magnetosensors remains to be established.

Molecular Oxygen Binding in the Mitochondrial Electron Transfer Flavoprotein.

Reactive oxygen species such as superoxide are potentially harmful byproducts of the aerobic metabolism in the inner mitochondrial membrane, and complexes I, II, III of the electron transport chain have been identified as primary sources. The mitochondrial fatty acid b-oxidation pathway may also play a yet uncharacterized role in reactive oxygen species generation, apparently at the level of the electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) and/or its redox partner electron-transfer flavoprotein (ETF). These enzymes comprise a key pathway through which electrons are sequentially shuttled from several dehydrogenases to the respiratory chain.

Low-intensity electromagnetic fields induce human cryptochrome to modulate intracellular reactive oxygen species.

Exposure to man-made electromagnetic fields (EMFs), which increasingly pollute our environment, have consequences for human health about which there is continuing ignorance and debate. Whereas there is considerable ongoing concern about their harmful effects, magnetic fields are at the same time being applied as therapeutic tools in regenerative medicine, oncology, orthopedics, and neurology. This paradox cannot be resolved until the cellular mechanisms underlying such effects are identified.

Magnetic sensitivity mediated by the Arabidopsis blue-light receptor cryptochrome occurs during flavin reoxidation in the dark.

Arabidopsis cryptochrome mediates responses to magnetic fields that have been applied in the absence of light, consistent with flavin reoxidation as the primary detection mechanism. Cryptochromes are highly conserved blue-light-absorbing flavoproteins which have been linked to the perception of electromagnetic stimuli in numerous organisms. These include sensing the direction of the earth's magnetic field in migratory birds and the intensity of magnetic fields in insects and plants.

Blue-light induced biosynthesis of ROS contributes to the signaling mechanism of Arabidopsis cryptochrome.

Cryptochromes are evolutionarily conserved blue light receptors with many roles throughout plant growth and development. They undergo conformational changes in response to light enabling interaction with multiple downstream signaling partners. Recently, it has been shown that cryptochromes also synthesize reactive oxygen species (ROS) in response to light, suggesting the possibility of an alternate signaling mechanism.

Direction-Dependent Effects of Combined Static and ELF Magnetic Fields on Cell Proliferation and Superoxide Radical Production.

Proliferation of human umbilical vein endothelial cells was stimulated by a nearly vertical 60 or 120 T static magnetic field (MF) in comparison to cells that were shielded against MFs. When the static field was combined with an extremely low frequency (ELF) MF (18 Hz, 30 T), proliferation was suppressed by a horizontal but not by a vertical ELF field. As these results suggested that the effects of an ELF MF depend on its direction in relation to the static MF, independent experiments were carried out to confirm such dependence using 50 Hz MFs and a different experimental model.

Blue-light induced accumulation of reactive oxygen species is a consequence of the Drosophila cryptochrome photocycle.

Cryptochromes are evolutionarily conserved blue-light absorbing flavoproteins which participate in many important cellular processes including in entrainment of the circadian clock in plants, Drosophila and humans. Drosophila melanogaster cryptochrome (DmCry) absorbs light through a flavin (FAD) cofactor that undergoes photoreduction to the anionic radical (FAD•-) redox state both in vitro and in vivo. However, recent efforts to link this photoconversion to the initiation of a biological response have remained controversial.

The Quantum Biology of Reactive Oxygen Species Partitioning Impacts Cellular Bioenergetics.

Quantum biology is the study of quantum effects on biochemical mechanisms and biological function. We show that the biological production of reactive oxygen species (ROS) in live cells can be influenced by coherent electron spin dynamics, providing a new example of quantum biology in cellular regulation. ROS partitioning appears to be mediated during the activation of molecular oxygen (O) by reduced flavoenzymes, forming spin-correlated radical pairs (RPs).

Blue-light dependent ROS formation by Arabidopsis cryptochrome-2 may contribute toward its signaling role.

Cryptochromes are blue-light absorbing flavoproteins with many important signaling roles in plants, including in de-etiolation, development, and stress response. They interact with downstream signaling partners such as transcription factors and components of the proteasome, and thereby alter regulation of nuclear gene expression in a light dependent manner. In a prior study, it has also been shown that Arabidopsis cry1 activation by blue light results in direct enzymatic conversion of molecular oxygen (O2) to ROS (reactive oxygen species) in vivo leading to cell death in overexpressing lines.

Inhibition of cellular proliferation and enhancement of hydrogen peroxide production in fibrosarcoma cell line by weak radio frequency magnetic fields.

This study presents experimental data for the effects of weak radio frequency (RF) magnetic fields on hydrogen peroxide (H2O2) production and cellular growth rates of fibrosarcoma HT1080 cells in vitro. Cells were exposed either to 45 µT static magnetic fields (SMFs)-oriented vertical to the plane of growth or to SMFs combined with weak 5 and 10 MHz RF magnetic fields of 10 µTRMS intensity perpendicular to the static field. Cell numbers were reduced up to 30% on Day 2 for the cells exposed to the combination of SMF and a 10 MHz RF magnetic field compared with the SMF control cells.

Spin biochemistry modulates reactive oxygen species (ROS) production by radio frequency magnetic fields.

The effects of weak magnetic fields on the biological production of reactive oxygen species (ROS) from intracellular superoxide (O2•-) and extracellular hydrogen peroxide (H2O2) were investigated in vitro with rat pulmonary arterial smooth muscle cells (rPASMC). A decrease in O2•- and an increase in H2O2 concentrations were observed in the presence of a 7 MHz radio frequency (RF) at 10 μTRMS and static 45 μT magnetic fields. We propose that O2•- and H2O2 production in some metabolic processes occur through singlet-triplet modulation of semiquinone flavin (FADH•) enzymes and O2•- spin-correlated radical pairs.

Modulation of hydrogen peroxide production in cellular systems by low level magnetic fields.

Increased generation of reactive oxygen species (ROS) and an altered redox status have long been observed in cancer cells, suggesting that ROS might be involved in the development of these cells. However, recent studies suggest that inducing an excess of ROS in cancer cells can be exploited for therapeutic benefits. Cancer cells in advanced stage tumors frequently exhibit multiple genetic alterations and high oxidative stress, suggesting that it might be possible to preferentially modulate the development of these cells by controlling their ROS production.

Static magnetic field sensitivity of endothelial cells.

In this manuscript, data demonstrating the magnetic sensitivity of human umbilical vein endothelial cells (HUVECs) is presented. The effects of low level fields (LLF; 0.2-1 µT), 30 and 120 µT magnetic fields on the proliferation of endothelial cells were investigated.

Reduction of the Earth's magnetic field inhibits growth rates of model cancer cell lines.

Small alterations in static magnetic fields have been shown to affect certain chemical reaction rates ex vivo. In this manuscript, we present data demonstrating that similar small changes in static magnetic fields between individual cell culture incubators results in significantly altered cell cycle rates for multiple cancer-derived cell lines. This change as assessed by cell number is not a result of apoptosis, necrosis, or cell cycle alterations.

Effects of weak static magnetic fields on endothelial cells.

Pulsed electromagnetic fields (PEMFs) have been used extensively in bone fracture repairs and wound healing. It is accepted that the induced electric field is the dose metric. The mechanisms of interaction between weak magnetic fields and biological systems present more ambiguity than that of PEMFs since weak electric currents induced by PEMFs are believed to mediate the healing process, which are absent in magnetic fields.

The effects of pulsed electromagnetic fields on the cellular activity of SaOS-2 cells.

Although pulsed electromagnetic fields (PEMFs) have been used for treatments of nonunion bone fracture healing for more than three decades, the underlying cellular mechanism of bone formation promoted by PEMFs is still unclear. It has been observed that a series of parameters such as pulse shape and frequency should be carefully controlled to achieve effective treatments. In this article, the effects of PEMFs with repetitive pulse burst waveform on the cellular activity of SaOS-2 osteoblast-like cells were investigated.